#include <bits/stdc++.h>
using namespace std;

string t = "nyanpass";
int n;
int cnt[100];

int main()
{
	scanf("%d", &n);
	for (int i = 0; i < n; i++){
		for (int j = 0; j < n; j++){
			string s;
			cin >> s;
			if (s == t) cnt[j]++;
		}
	}
	
	int q = 0, r = -1;
	for (int i = 0; i < n; i++){
		if (cnt[i] == n - 1){
			q++;
			r = i;
		}
	}
	
	if (q != 1) puts("-1");
	else printf("%d\n", r + 1);
}